Reduction of Hysteresis in Hybrid Perovskite Transistors by Solvent-Controlled Growth.

Farjana Haque,Mallory Mativenga,Ravindra Naik Bukke

doi:10.3390/ma14102573

Abstract

The effect of crystallization process speed on the morphology of solution-processed methyl ammonium lead iodide (MAPbI3) thin films is investigated. Crystallization speed is controlled by varying the number of annealing steps, temperature, and resting time between steps. The resting period allows solvent-controlled growth (SCG) in which crystallization progresses slowly via an intermediate phase—during which solvents slowly evaporate away from the films. SCG results in fewer residues, fewer pinholes, and larger grain sizes. Consequently, thin-film transistors with SCG MAPbI3 exhibit smaller hysteresis in their current-voltage characteristics than those without, demonstrating the benefits of SCG toward hysteresis-free perovskite devices.

Highlights

Organic–inorganic hybrid perovskites such as methylammonium lead iodide (CH3 NH3 PbI3 or MAPbI3 ) have recently emerged as promising candidates for highperformance and low-cost optoelectronic devices [1,2]
We investigate the effects of crystallization process speed on the morphology of the hybrid perovskite methyl ammonium lead iodide (MAPbI3 ) and its impact on hysteresis in the electrical characteristics of ambient-air-processed MAPbI3 thin-film transistors (TFTs)
solvent-controlled growth (SCG) decreases the total number of defects and grain boundaries in MAPbI3 —thereby significantly reducing hysteresis in MAPbI3 TFTs

Summary

Introduction

Organic–inorganic hybrid perovskites such as methylammonium lead iodide (CH3 NH3 PbI3 or MAPbI3 ) have recently emerged as promising candidates for highperformance and low-cost optoelectronic devices [1,2]. In solar cells, these materials have excelled as light harvesters, reaching record power conversion efficiencies of over 20% in their early stages of development [3]. Instability in the performance of these devices, especially the hysteresis in their current-voltage (I-V) characteristics, still limits their application in commercial products [8,9,10,11,12,13,14,15,16,17,18,19]. Ion migration leads to a significant screening of the applied electric field in solar cells and LEDs, leading to measurement speed, time, or history-dependent hysteresis in their I-V characteristics [13,16,18]

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Conclusion